Integrated circuits (ICs) and other electronic devices often include arrangements of interconnected field effect transistor (FET) devices, also called metal-oxide-semiconductor field effect transistors (MOSFETs). A typical FET device includes a gate electrode as a control electrode, and spaced apart source and drain electrodes. A control voltage applied to the gate electrode controls the flow of current through a controllable conductive channel between the source and drain electrodes.
Power transistor devices are designed to be tolerant of the high currents and voltages that are present in switching applications that previously relied upon electromechanical switches. In a conduction (or ON) state, power transistor devices may handle currents that range from several Amperes to several hundred Amperes. The applications may also involve the power transistor devices blocking high voltages during an OFF state, e.g., 25 Volts or more, without breaking down. One type of power transistor device is a trench FET device. In trench FET devices, the gate electrode is disposed in a trench to form a vertical channel. Significant effort has been directed toward the formation of bidirectional trench FETs that are capable of switching high currents through their conduction electrodes while blocking high voltages applied to the conduction electrodes.
Some prior art bidirectional trench FET devices utilize a boron doped P-region body and a P+ link connects the P-region body to the P-body electrode. This process can be readily implemented. However, this process is not efficient at removing holes generated by impact ionization near the drain and body junction due to a high resistive path. The high resistive path of the P-body in parasitic bipolar induces bipolar snapback at lower impact ionization resulting in low blocking voltage and limited safe operating area (SOA). Therefore, a need exists in the art of bidirectional trench FET devices to resolve the above discussed problem.